Stylus device



April 30, 1946.

' E o. THOMPSON STYLUS 'DEVICE Filed Nov. 6, 1942 il l 9 F Patented Apr.30, 1946 Elmer 0. Thompson,

Grasmere, N. Y.,

asslgnor to Phllco Radio and Television Corporation, Philadelphia, Pa...a corporation of Delaware Original application Se 357,322. her 6, 1942,Serial 2 Claims.

This invention relates to stylus devices for use in phonographs of thetype employing sound records having a laterally cut groove. Thisapplication is a division of my copending application Serial No.357,322, filed September 18, 1940, now Patent No. 2,359,808, grantedOctober 10, 1944.

The principal object of th present invention is to provide a stylusdevice which is adapted to transmit very accurately the lateralundulations of a record groove to a suitable translating mechanism, andto ailord a maximum of protection 01' the stylus and the record frominjury such as might be caused by accidentally dropping the stylus ontoa record.

A more specific object of the invention is to provide a stylus devicecomprising a rigid element to which the undulations are-to betransmitted, a stylus laterally oflset from said element, and an arminterconnecting the rigid element and the stylus, said arm havingsubstantially greater width than thickness and having transverse bendstherein, whereby it is very rigid to lateral movements of the stylus,but is highly flexible to vertical movements thereof.

Other objects and features of the invention will appear hereinafter.

In the accompanvingdrawing:

,ig. 1 is an enlarged perspective view of a stylus device embodying theinvention, the particular form of the device illustrated being thatshown in the aforementioned copending application;

Fig. 2 is a face view of the assembly including the device of Fig. 1according to the aforementioned copending application;

Fig. 3 is a plan view of the same; Fig. 4 is a side elevational view ofthe same; and

Fig. 5 is a sectional view of the same.

Referring particularly to Fig. 1, in accordance with the presentinvention, there is provided a stylus device comprising a rigid shank I,a stylus 2 laterally offset from the shank I, and an arm 3interconnecting the shank and the stylus, which serves to transmit veryaccurately the lateral movements of the stylus to the rigid shank andwhich also provides a highly flexible mounting for the stylus in avertical sense. This arm is formed from a strip of spring material, suchas metal, and it has transverse bends 4 and 5, thus I portions areformed providing an .inclined body portion 6 and'end portions 1 and 8extending at appreciable angles ,from the body portion.

Since the lateral movements oi the stylus 2 are ptember 18, 1940, SerialNo. Divided and this application Novemapplied to arm 3 in the directionof its width, which is substantially greater than its thickness, the armis rigid to such movements. However, the lateral bends 4 and 5 greatlyincrease the rigidity of the arm to such movements, with the result thatthe lateral undulations of a record groove are transmitted veryaccurately from the stylus to the rigid shank i. the bent structure ofthe arm 3 disposes the record-engaging portion of the stylus well belowthe lower end 01 the rigid shank, and the stylus is due to violentcontact between the two, as would occur, for example, if the droppedonto a record.

In the specific form of the device illustrated, the stylus 2, which maytake the form of a sapphire element, is mounted on the free end of arm 3by means of a rivet 9, and the other end of arm 3 is riveted to thelower end of shank I at III, as shown more clearly in Figs. 2, 4 and 5.It will be understood, however, that any other arrangement of the partsmay be employed so long as the principles of the inventionare adheredto.

In the employment of the stylus device in a photoelectric translatingsystem of the type disclosed in the aforementioned parent application,the lateral movements of the stylus transmitted by the arm 3 cause theshank I to rotate slightly about its axis, to the'end that a lightreflector II mounted on shank I is oscillated to eifect thephotoelectric translating action. While the present invention is notparticularly concerned with the specific adaptation of the stylus devicedisclosed in the said parent application, Figs. 2 to 5 show more clearlythe manner in which the device is utilized in such adaptation and thusserve to illustrate one possible arrangement of the device in aphonograph pick-up mechanism.

' Referring to Figs. 2 to 5, the armature assembly including shank l issupported by resilient bearings I2 and I3 (see Fig. 5) within a pair offrame members I4 and I5 whose upper and lower to provide bearingretainers I6 and I1. The shank I has a non-circular pori'ormed so as tonormally main- I I in a predetermined position. Owing to the resilienceof the bearings, the shank I and the reflector II carried thereby arepermitted to rotate slightly in response to At the same time,

stylus were accidentally lateral movements of the stylus. The entireassembly is held together passing through the complementary framemembers. A guard 20 is carried by one of the frame members and thestylus is adapted to recede within. the guard under the impetus ofvertical forces.

From the foregoing description, it will be seen that the inventionprovides a. novel stylus device having the ieatures hereinbeiorementioned.

It will be understood, of course, that the invention is not limited tothe specific disclosure, but is capable of various changes andmodifications within the scope of the appended claims. The stylus devicemay; of course, be used with any known form of phonograph pick-upmechanism.

I claim:

1. In a stylus device for use with a phonograph record having alaterally undulating groove. an elongated vertical armature, means forsupportme said armature for limited rotation about its longitudinalaxis, a stylus laterally offset from by means 0! screws I! 2,s99,sss Jsaid armature, and a vertically deflectible arm of substantially greaterwidth than thickness connecting said stylus to said armature ioreflecting limited rotation of the armature about its longitudinal axisin response to lateral displacements of the stylus.

2. In a stylus device for use with a phonograph record having alaterally undulating groove, an elongated vertical armature, means forsupportfor longitudinal axis, a stylus laterally oilset from saidarmature, a vertically deflectible arm or substantially greater widththan thickness connecting said stylus to said armature for effectinglimited rotation of the armature about its longitudinal axis in responseto lateral displacements of the stylus, and guard means on saidsupporting means in cooperative relation with said stylus for protectingthe latter against abnormal vertical iorces.

EIMER O. THOMPSON.

